Functionalised nanofibers for water treatment

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2023-12
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ENGLISH ABSTRACT: Access to safe drinking water and adequate sanitation is a pressing global issue with significant implications for health, welfare, and economic development. Nanotechnology holds promise in addressing the challenges associated with water purification. Specifically, functionalized nanofibers have emerged as a potential solution for water treatment. In one study, antimicrobial poly (vinyl alcohol) nanofibers were produced by incorporating AquaQure biocide into the polymer solution. These nanofibers demonstrated strong antimicrobial properties, achieving a substantial reduction in populations of various bacteria strains including E. coli, S. aureus, S. typhimurium, P. aeruginosa and K. pneumoniae bacteria. Additionally, immobilized enzymes were explored as a means of breaking down biofilms and preventing their formation. Non‐woven mats made of Polyacrylonitrile (PAN) were successfully fabricated using different electrospinning processes, retaining over 80% of the enzymes' specific activity. These functionalized membranes offer potential applications in the water filtration industry by preventing biological fouling of membranes. A cartridge filter where activated carbon was encased in electrospun nanofibers was manufactured and evaluated. Culturable methods indicated that the filter could produce 3 l of potable water. However, when using PCR assays, it was unable to eliminate Klebsiella spp., Legionella spp., Pseudomonas spp., and Yersinia spp. from the filtered rainwater harvested tank water. This suggested that these bacteria were in the non‐ culturable but viable state and passed through the filter. Furthermore, adenovirus, being small enough to pass through the membrane's pores, was not effectively removed by the cartridge filter. Overall, this research demonstrates the potential of functionalized nanofibers and immobilized enzymes in developing advanced filter media for water filtration. However, challenges remain in effectively removing certain pathogens and viruses, highlighting the need for further improvements and innovations in the field.
AFRIKAANSE OPSOMMING: Toegang tot veilige drinkwater en voldoende sanitasie is 'n ernstige globale probleem met belangrike gevolge vir gesondheid, welvaart en ekonomiese ontwikkeling. Nanotegnologie bied belowende moontlikhede om die uitdagings wat gepaard gaan met water suiwering aan te spreek. Gefunksionaliseerde nanovesels is 'n potensiële oplossing vir waterbehandeling. In hierdie studie is antimikrobiese poli (vinielalkohol) nanovesels vervaardig deur die inkorporasie van AquaQure biosied in die polimeeroplossing. Hierdie nanovesels was antimikrobies teen verskillende bakteriestamme. Vorige navorsing het ook die doeltreffendheid van sekere verbindings, soos gebromeerde furanone, beklemtoon om bakteriële aanhegting te inhibeer en hulle te deaktiveer. Nanovesel membrane wat hierdie verbindings inkorporeer, het antimikrobiese en inhiberende eienskappe ten opsigte van selhegting teen bakteriestamme soos P. aeruginosa, E. coli, S. typhimurium, S. aureus en K. pneumoniae getoon. Verder is geïmmobiliseerde ensieme ondersoek as 'n manier om biofilms af te breek en hul vorming te voorkom. Nie‐geweefde matte van poliakrilonitriel (PAN) is suksesvol vervaardig deur verskillende elektrospinprosesse te gebruik, terwyl meer as 80% van die ensieme se spesifieke aktiwiteit behou is. Hierdie gefunksionaliseerde membrane bied potensiële toepassings in die waterfiltrasie‐industrie. Die doeltreffendheid van ‘n PVA antimikrobiese nanovesel/geaktiveerde koolstofkolom filter is evalueer deur gebruik te maak van kweek metodes en PCR‐toetse om patogene bakterieë op te spoor. Deur kweekmentodes te gebruik om patogene op te spoor, kon die filter 3 liter water van drinkbare gehalte produseer. PKR toetse het egter getoon die die nie in staat was om Klebsiella spp., Legionella spp., Pseudomonas spp. en Yersinia spp. uit die gefiltreerde tenkwater te elimineer nie. Hierdie was waarskynlik omdat die organismes in ‘n lewensvatbare toestand verkeer het maar nie nie gekweek kon word nie. Verder is adenovirus, wat klein genoeg is om deur die porieë van die membraan te gaan, nie doeltreffend verwyder deur die filter nie. Alles in ag genome, toon hierdie navorsing die potensiaal van antimikrobiese nanovesels en geïmmobiliseerde ensieme.
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Thesis (PhD)--Stellenbosch University, 2023.
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